Technical Field
The present invention pertains to surgical cutting instruments having relatively movable elongate inner and outer tubes arranged to cut tissue through a cutting window proximate the distal end of the outer tube. More particularly, the invention relates to improvements in selectively orienting the cutting window to facilitate utilization of the surgical instrument.
There is a genre of surgical instruments for use in closed, or endoscopic, surgery that are elongated to permit distal ends of the instruments to be positioned at internal surgical sites through one or more small portals cut into the patient's body. Examples of such instruments are found in U.S. Pat. No. 5,217,478 (Rexroth), U.S. Pat. No. 5,061,238 (Shuler) and U.S. Pat. No. 4,646,738 (Trott). The disclosures in all of these patents and patent application are expressly incorporated herein. Such surgical cutting instruments include relatively movable, cooperating, concentric inner and outer tubes elongated longitudinally so that the distal ends of the tubes can be positioned at internal surgery sites while their proximal ends are secured, externally of the patient's body, in a handpiece. The handpiece may contain a selectively actuable motor, or may transmit forces from an external motor, to rotate or otherwise move the inner tube relative to the fixed outer tube. At the distal end of the outer tube there is commonly formed a cutting opening or window to receive bodily tissue. The distal end of the inner tube is formed with a cutting surface or edge to engage the tissue through the cutting opening when the inner tube is moved relative to the outer tube. The cutting surface or edge of the inner tube cooperates with the cutting opening in the outer tube to shear, abrade or otherwise cut the tissue as the cutting surface moves past the cutting opening. In this regard, the cutting surface and the cutting opening may be configured as desired to produce a variety of cutting functions, such as whisker cutting, synovial resection, arthroplasty burring or abrading, side cutting, meniscus cutting, trimming, full radius resection and end cutting as appropriate for diverse types of tissue, such as soft tissue, cartilage and bone. The inner and outer tubes may be straight, or they may be bent at an angle suitable for a particular surgical application. Suction is normally produced through the handpiece and the lumen of the inner tube to permit cut tissue to be aspirated from the surgical site through the inner tube.
In the instruments described above, the outer tube has a plastic hub with a positioning tab keyed and retained in a corresponding slot in the handpiece. Since the outer tube is positionally fixed relative to its hub, the cutting window at the distal end of the inner tube is positionally fixed relative to the handpiece. The handpiece is typically designed to be held in the surgeon's hand in one optimum angular orientation about its axis, since the pushbutton motor controls on the handpiece must be positioned at the surgeon's finger tips. In many situations arising during surgery, the surgeon is required to either bend his or her wrist awkwardly, or rotate the handpiece to a position wherein the controls are not conveniently accessible, in order to position the cutting window properly at the surgical site.